Development and Validation of the Rating of CKD Knowledge Among Older Adults (Know-CKD) With Kidney Failure

RATIONALE & OBJECTIVE

Few older adults with kidney failure engage in shared decision making (SDM) for kidney replacement therapy. The lack of instruments to assess SDM-relevant knowledge domains may contribute to this. We assessed the reliability and validity of a new instrument, the Rating of CKD Knowledge Older Adults (Know-CKD).

STUDY DESIGN

Multistage process, including a stakeholder-engaged development phase, pilot testing, and validation of a knowledge instrument using a cross-sectional survey of older adults with CKD.

SETTING & PARTICIPANTS

363 patients aged 70+years with nondialysis advanced chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR]<30mL/min/1.73m2) in Boston, Chicago, Portland, ME, and San Diego from June 2018 and January 2020.

EXPOSURE

Educational level, higher literacy (Single Item Literacy Screener [SILS]) and numeracy (Subjective Numeracy Scale [SNS]), having participated in clinic-sponsored dialysis education, and self-reported "feeling informed" about options for treatment.

OUTCOME

Validity and reliability of the Know-CKD instrument.

ANALYTICAL APPROACH

Reliability was assessed with the Kuder-Richardson-20 coefficient. Construct validity was demonstrated by testing a priori hypotheses using t test, analysis of variance (ANOVA) tests, and linear regression analyses.

RESULTS

The mean (± SD) participant age was 77.6±5.9 years, and mean eGFR was 22.7±7.2mL/min/1.73m2; 281 participants (78%) self-reported as White. The 12-item Know-CKD assessment had good reliability (Kuder-Richardson-20 reliability coefficient=0.75), and a mean score of 58.2% ± 22.3 SD. The subscales did not attain acceptable reliability. The proportion answering correctly on each item ranged from 20.1% to 91.7%. In examining construct validity, the hypothesized associations held; Know-CKD significantly associated with higher education (β=6.98 [95% CI, 1.34-12.61], P=0.02), health literacy (β = -12.67 [95% CI, -19.49 to-5.86], P≤0.001), numeracy per 10% higher (β=1.85 [95% CI, 1.02-2.69], P≤0.001), and attendance at dialysis class (β=18.28 [95% CI, 13.30-23.27], P≤0.001). These associations were also observed for the subscales except for prognosis (not associated with literacy or numeracy).

LIMITATIONS

Know-CKD is only available in English and has been used only in research settings.

CONCLUSIONS

For older adults facing dialysis initiation decisions, Know-CKD is a valid, reliable, and easy to administer measure of knowledge. Further research should examine the relationship of kidney disease knowledge and SDM, patient satisfaction, and clinical outcomes.

PLAIN-LANGUAGE SUMMARY

The Rating of CKD Knowledge Among Older Adults (Know-CKD) study measures knowledge of chronic kidney disease (CKD) and is designed for older adults. Most existing knowledge measures for CKD focus on people of all ages and all CKD stages. This measure is useful because it will allow researchers to assess how well patient education efforts are working. Patient education is a way to help patients make decisions about their care. We describe how the measure was developed by a team of doctors, researchers, and patients, and how the measure performed among persons with advanced CKD aged 70 years and older. Know-CKD can inform efforts to improve shared decision-making research and practice for older patients with kidney disease.

Effectiveness of an Intervention to Improve Decision Making for Older Patients With Advanced Chronic Kidney Disease : A Randomized Controlled Trial

BACKGROUND

Older patients with advanced chronic kidney disease (CKD) face difficult decisions about managing kidney failure, frequently experiencing decisional conflict, regret, and treatment misaligned with preferences.

OBJECTIVE

To assess whether a decision aid about kidney replacement therapy improved decisional quality compared with usual care.

DESIGN

Multicenter, randomized, controlled trial. (ClinicalTrials.gov: NCT03522740).

SETTING

8 outpatient nephrology clinics associated with 4 U.S. centers.

PARTICIPANTS

English-fluent patients, 70 years and older with nondialysis CKD stages 4 to 5 recruited from 2018 to 2020.

INTERVENTION

DART (Decision-Aid for Renal Therapy) is an interactive, web-based decision aid for older adults with CKD. Both groups received written education about treatments.

MEASUREMENTS

Change in the decisional conflict scale (DCS) score from baseline to 3, 6, 12, and 18 months. Secondary outcomes included change in prognostic and treatment knowledge and change in uncertainty.

RESULTS

Among 400 participants, 363 were randomly assigned: 180 to usual care, 183 to DART. Decisional quality improved with DART with mean DCS declining compared with control (mean difference, -8.5 [95% CI, -12.0 to -5.0]; P < 0.001), with similar findings at 6 months, attenuating thereafter. At 3 months, knowledge improved with DART versus usual care (mean difference, 7.2 [CI, 3.7 to 10.7]; P < 0.001); similar findings at 6 months were modestly attenuated at 18 months (mean difference, 5.9 [CI, 1.4 to 10.3]; P = 0.010). Treatment preferences changed from 58% "unsure" at baseline to 28%, 20%, 23%, and 14% at 3, 6, 12, and 18 months, respectively, with DART, versus 51% to 38%, 35%, 32%, and 18% with usual care.

LIMITATION

Latinx patients were underrepresented.

CONCLUSION

DART improved decision quality and clarified treatment preferences among older adults with advanced CKD for 6 months after the DART intervention.

PRIMARY FUNDING SOURCE

Patient-Centered Outcomes Research Institute (PCORI).

Advantages, Limitations, and Clinical Considerations in Using Cystatin C to Estimate GFR

Cystatin C has been shown to be a reliable and accurate marker of kidney function across diverse populations. The 2012 Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommended using cystatin C to confirm the diagnosis of chronic kidney disease (CKD) determined by creatinine-based estimated glomerular filtration rate (eGFR) and to estimate kidney function when accurate eGFR estimates are needed for clinical decision-making. In the efforts to remove race from eGFR calculations in the United States, the National Kidney Foundation (NKF) and American Society of Nephrology (ASN) Joint Task Force recommended increasing availability and clinical adoption of cystatin C to assess kidney function. This review summarizes the key advantages and limitations of cystatin C use in clinical practice. Our goals were to review and discuss the literature on cystatin C; understand the evidence behind the recommendations for its use as a marker of kidney function to diagnose CKD and risk stratify patients for adverse outcomes; discuss the challenges of its use in clinical practice; and guide clinicians on its interpretation.

MO373: How to Decide Whether Creatinine or Cystatin C is More Accurate for Kidney Function Assessment in Older Adults

BACKGROUND AND AIMS

The gold standard for evaluation of kidney function is measured GFR [mGFR] which is challenging to perform in clinical practice. Serum creatinine and cystatin C are used to estimate GFR clinically, but neither is a perfect marker. Within any given individual, the estimated glomerular filtration rate (eGFR) can be widely different when using serum creatinine [eGFRCr] vs. cystatin C [eGFRCys]. We investigated which was closest to mGFR in elderly outpatients when results between these two eGFRs were discrepant.

METHOD

About 657 older ambulatory participants of the population-based Berlin Initiative Study (BIS) had GFR measured by iohexol plasma clearance (mGFR), as well as serum creatinine and cystatin C levels. eGFRCr and eGFRCys were calculated using the 2009 and 2012 CKD-EPI equations, respectively. The cohort was divided into two groups based on which of these eGFR estimates was lowest. Bias (defined as ‘eGFR-mGFR’), imprecision (standard deviation [interquartile range] of bias), as well as proportion within 30% (P30) were calculated.

RESULTS

Mean (±SD) age was 78 (±6) years, eGFRCys was 59 (±23), mean eGFRCr was 64 (±20) and mGFR was 55 (±20) mL/min/1.73 m2. Mean (±SD) body mass index was 28 (4) kg/m2 58% were men, and 26% had diabetes mellitus. Two-thirds of participants (448/657 = 68%) had eGFRCys &lt; eGFRCr. Regardless of which group participants were in, the lower of the two eGFR estimates was the one less biased compared to mGFR. Among those in whom eGFRCr ≤ eGFRCys, 80% (=168/209) had eGFRCr closer to mGFR than eGFRCys; among those in whom eGFRCys &lt; eGFRCr, 74% (=333/448) had eGFRCys closer to mGFR than eGFRCr (Figure). P30 was 86% for eGFRCr when it was the lower estimate, and was 90% for eGFRCys when it was the lower estimate (Table).

CONCLUSION

In a population of community-dwelling older adults, the lower value between eGFRCys and eGFRCr was closest to mGFR in 76% of participants.

The Relationship of Kidney Tubule Biomarkers with Brain Imaging in CKD Patients in SPRINT

Urine biomarker concentrations reflecting kidney tubule injury and dysfunction were not associated with brain MRI measures.Higher eGFR was associated with lower total brain cerebral blood flow.This is the first evaluation of the relationship of kidney tubule biomarkers with brain imaging by MRI in patients with CKD.

Perceptions of Telehealth vs In-Person Visits Among Older Adults With Advanced Kidney Disease, Care Partners, and Clinicians

Importance

Telehealth has been posited as a cost-effective means for improving access to care for persons with chronic conditions, including kidney disease. Perceptions of telehealth among older patients with chronic illness, their care partners, and clinicians are largely unknown but are critical to successful telehealth use and expansion efforts.

Objective

To identify patient, care partner, and nephrologists' perceptions of the patient-centeredness, benefits, drawbacks of telehealth compared to in-person visits.

Design, Setting, and Participants

This qualitative study used semistructured interviews conducted from August to December 2020 with purposively sampled patients (aged 70 years or older, chronic kidney disease stages 4 to 5), care partners, and clinicians in Boston, Massachusetts; Chicago, Illinois; Portland, Maine; and San Diego, California.

Main Outcomes and Measures

Participants described telehealth experiences, including factors contributing to and impeding engagement, satisfaction, and quality of care. Thematic analysis was used to analyze data.

Results

Of 60 interviews, 19 (32%) were with clinicians, 30 (50%) with patients, and 11 (18%) with care partners; 16 clinicians (84%) were nephrologists; 17 patient participants (43%) were non-Hispanic Black, and 38 (67%) were women. Four overarching themes characterized telehealth's benefits and drawbacks for patient-centered care among older, chronically ill adults: inconsistent quality of care, patient experience and engagement, loss of connection and mistrust (eg, challenges discussing bad news), and disparities with accessing telehealth. Although telehealth improved convenience and care partner engagement, participants expressed concerns about clinical effectiveness and limitations of virtual physical examinations and potentially widening disparities in access. Many participants shared concerns about harms to the patient-clinician relationship, limited ability to comfort patients in virtual settings, and reduced patient trust.

Conclusions and Relevance

Older patients, care partners, and kidney clinicians (ie, nephrologists and physician assistants) shared divergent views of patient-centered telehealth care, especially its clinical effectiveness, patient experience, access to care, and clinician-patient relationship. Understanding older patients' and kidney clinicians' perceptions of telehealth elucidate barriers that should be addressed to promote high-quality care and telehealth use.

Advance Care Planning in Older Adults with CKD: Patient, Care Partner, and Clinician Perspectives

BACKGROUND

Older patients with advanced CKD are at high risk for serious complications and death, yet few discuss advance care planning (ACP) with their kidney clinicians. Examining barriers and facilitators to ACP among such patients might help identify patient-centered opportunities for improvement.

METHODS

In semistructured interviews in March through August 2019 with purposively sampled patients (aged ≥70 years, CKD stages 4-5, nondialysis), care partners, and clinicians at clinics in across the United States, participants described discussions, factors contributing to ACP completion or avoidance, and perceived value of ACP. We used thematic analysis to analyze data.

RESULTS

We conducted 68 semistructured interviews with 23 patients, 19 care partners, and 26 clinicians. Only seven of 26 (27%) clinicians routinely discussed ACP. About half of the patients had documented ACP, mostly outside the health care system. We found divergent ACP definitions and perspectives; kidney clinicians largely defined ACP as completion of formal documentation, whereas patients viewed it more holistically, wanting discussions about goals, prognosis, and disease trajectory. Clinicians avoided ACP with patients from minority groups, perceiving cultural or religious barriers. Four themes and subthemes informing variation in decisions to discuss ACP and approaches emerged: (1) role ambiguity and responsibility for ACP, (2) questioning the value of ACP, (3) confronting institutional barriers (time, training, reimbursement, and the electronic medical record, EMR), and (4) consequences of avoiding ACP (disparities in ACP access and overconfidence that patients' wishes are known).

CONCLUSIONS

Patients, care partners, and clinicians hold discordant views about the responsibility for discussing ACP and the scope for it. This presents critical barriers to the process, leaving ACP insufficiently discussed with older adults with advanced CKD.

Association of Urine Biomarkers of Kidney Tubule Injury and Dysfunction With Frailty Index and Cognitive Function in Persons With CKD in SPRINT

RATIONALE & OBJECTIVE

The associations of the glomerular markers of kidney disease, estimated glomerular filtration rate (eGFR) and albuminuria, with frailty and cognition are well established. However, the relationship of kidney tubule injury and dysfunction with frailty and cognition is unknown.

STUDY DESIGN

Observational cross-sectional study.

SETTING & PARTICIPANTS

2,253 participants with eGFR<60mL/min/1.73m² in the Systolic Blood Pressure Intervention Trial (SPRINT).

EXPOSURE

Eight urine biomarkers: interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), chitinase-3-like protein 1 (YKL-40), monocyte chemoattractant protein 1 (MCP-1), α₁-microglobulin (A1M), β₂-microglobulin (B2M), and uromodulin (Umod).

OUTCOME

Frailty was measured using a previously validated frailty index (FI), categorized as fit (FI≤0.10), less fit (0.10<FI≤0.21), and frail (FI>0.21). Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA).

ANALYTICAL APPROACH

Associations between kidney tubule biomarkers with categorical FI were evaluated using multinomial logistic regression with the fit group as the reference. Cognitive function was evaluated using linear regression. Models were adjusted for demographic, behavioral, and clinical variables including eGFR and urine albumin.

RESULTS

Three of the 8 urine biomarkers of tubule injury and dysfunction were independently associated with FI. Each 2-fold higher level of urine KIM-1, a marker of tubule injury, was associated with a 1.22 (95% CI, 1.01-1.49) greater odds of being in the frail group. MCP-1, a marker of tubulointerstitial fibrosis, was associated with a 1.30 (95% CI, 1.04-1.64) greater odds of being in the frail group, and A1M, a marker of tubule reabsorptive capacity, was associated with a 1.48 (95% CI, 1.11-1.96) greater odds of being in the frail group. These associations were independent of confounders including eGFR and urine albumin, and were stronger than those of urine albumin with FI (1.15 [95% CI, 0.99-1.34]). Higher urine B2M, another marker of tubule reabsorptive capacity, was associated with worse cognitive scores at baseline (β: -0.09 [95% CI, -0.17 to-0.01]). Urine albumin was not associated with cognitive function.

LIMITATIONS

Cross-sectional design, and FI may not be generalizable in other populations.

CONCLUSIONS

Urine biomarkers of tubule injury, fibrosis, and proximal tubule reabsorptive capacity are variably associated with FI and worse cognition, independent of glomerular markers of kidney health. Future studies are needed to validate these results among other patient populations.

Individualized Cool Dialysate as an Effective Therapy for Intradialytic Hypotension and Hemodialysis Patients' Perception

Intradialytic hypotension (IDH) is the most common dialytic complication. Recurrent episodes of ischemia secondary to hemodynamic instability are associated with cardiomyopathy, increased risk of thrombosis of arteriovenous fistula, decreased quality of life, and increased mortality. Cool dialysate may be an effective approach to reducing intradialytic hypotension by promoting peripheral vasoconstriction. Most studies to date are small and do not employ individualized cool dialysates (ICD). The study consisted of standard and cool phases, with patients as their own controls. During the standard phase, participants underwent hemodialysis (HD) at their usual dialysate temperature at 37°C for six consecutive hemodialysis sessions. In the cool phase, the dialysate temperature was set at the core baseline temperature -0.5°C for six more sessions. We compared hemodynamic parameters during the standard and cool phases. A total of 93 participants were included. The number of IDH episodes during the standard and cool phases were 3.3 ± 2.8 and 2.0 ± 2.2 per patient respectively (P < 0.001). Other hemodynamic parameters including lowest intradialytic mean arterial pressure were significantly increased with ICD. We found that there was a high baseline rate of feeling cold among all participants and it increased after the implementation of ICD; however, the dropout rate was approximately 5%. ICD is an effective tool to decrease the frequency of IDH in the HD population and we provide a pragmatic, real-world approach to implement this technique.

Anthropometric measures of obesity and renal artery calcification: Results from the Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Renal artery calcium (RAC) has been linked to several cardiovascular disease (CVD) risk factors, including age, male gender, and hypertension. The purpose of this study was to determine whether anthropometric measures of obesity are associated with presence of RAC.

METHODS

We studied 1287 community-dwelling adults enrolled in the Multi-Ethnic Study of Atherosclerosis. Logistic regression models adjusted for CVD risk factors were used to examine body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) as primary predictors of RAC.

RESULTS

Study participants had a mean age of 67.7 years, 55.7% were female, and 36.8% were non-Hispanic White. Prevalence of RAC was 33.3%. WC and WHR as continuous variables were not significant with adjustment. Subjects with high WC, as defined by World Health Organization cut-offs, had significantly higher odds for RAC in the fully adjusted model. BMI and HC were not significantly associated with RAC in any models.

CONCLUSIONS

In this community-based sample of older adults, higher levels of WC are significantly associated with RAC independently of CVD risk factors. Adults who meet World Health Organization criteria for high WC may be at higher risk for complications of calcified atherosclerosis in the renal arteries.

Long-term trends in the prevalence of chronic kidney disease and the influence of cardiovascular risk factors in Norway

Surveillance of chronic kidney disease (CKD) prevalence over time and information on how changing risk factors influence this trend are needed to evaluate the effects of general practice and public health interventions. Because very few studies addressed this, we studied the total adult population of a demographically stable county representative of Norway using cross-sectional studies 10 years apart (Nord-Trøndelag Health Study (HUNT)2 and Nord-Trøndelag Health Study (HUNT)3, 65,237 and 50,586 participants, respectively). Thorough quality-control procedures and comparisons of methods over time excluded analytical drift, and multiple imputations of missing data combined with nonattendance weights contributed to unbiased estimates. CKD prevalence remained stable in Norway from 1995 through 1997 (11.3%) to 2006 through 2008 (11.1%). The association of survey period with CKD prevalence was modified by a strong decrease in blood pressure, more physical activity, and lower cholesterol levels. Without these improvements, a 2.8, 0.7, and 0.6 percentage points higher CKD prevalence could have been expected, respectively. In contrast, the prevalence of diabetes and obesity increased moderately, but the proportion of diabetic patients with CKD decreased significantly (from 33.4% to 28.6%). A CKD prevalence of 1 percentage point lower would have been expected without these changes. Thus, CKD prevalence remained stable in Norway for more than a decade in association with marked improvements in blood pressure, lipid levels, and physical activity and despite modest increases in diabetes and obesity.

The associations of adipokines with selected markers of the renin-angiotensinogen-aldosterone system: the multi-ethnic study of atherosclerosis

Among obese individuals, increased sympathetic nervous system activity results in increased renin and aldosterone production, as well as renal tubular sodium reabsorption. This study determined the associations between adipokines and selected measures of the reninangiotensinogen-aldosterone system (RAAS). The sample was 1,970 men and women from the Multi-Ethnic Study of Atherosclerosis who were free of clinical cardiovascular disease at baseline and had blood assayed for adiponectin, leptin, plasma renin activity (PRA) and aldosterone. The mean age was 64.7 years and 50% were female. The mean (SD) PRA and aldosterone were 1.45 (0.56) ng/ml and 150.1 (130.5) pg/ml, respectively. After multivariable adjustment, a 1-SD increment of leptin was associated with a 0.55 ng/ml higher PRA and 8.4 pg/ml higher aldosterone (p < 0.01 for both). Although adiponectin was not significantly associated with PRA levels, the same increment in this adipokine was associated with lower aldosterone levels (−5.5 pg/ml, p = 0.01). Notably, the associations between aldosterone and both leptin and adiponectin were not materially changed with additional adjustment for PRA. Exclusion of those taking anti-hypertensive medications modestly attenuated the associations. The associations between leptin and both PRA and aldosterone were not different by gender but were significantly stronger among non-Hispanic Whites and Chinese Americans than African and Hispanic Americans (p < 0.01). The findings suggest that both adiponectin and leptin may relevant to blood pressure regulation via the RAAS, that the associations appear to be robust to anti-hypertension medication use and that the associations are likely different by ethnicity.

Higher leptin is associated with hypertension: the Multi-Ethnic Study of Atherosclerosis

Adipokines are secreted from adipose tissue, influence energy homeostasis and may contribute to the association between obesity and hypertension. Among 1897 participants enrolled in the Multi-Ethnic Study of Atherosclerosis, we examined associations between blood pressure and leptin, tumor necrosis factor-α (TNFα), resistin and total adiponectin. The mean age and body mass index (BMI) was 64.7 years and 28.1, respectively, and 50% were female. After adjustment for risk factors, a 1-s.d.-increment higher leptin level was significantly associated with higher systolic (5.0 mm Hg), diastolic (1.9), mean arterial (2.8) and pulse pressures (3.6), as well as a 34% higher odds for being hypertensive (P<0.01 for all). These associations were not materially different when the other adipokines, as well as BMI, waist circumference or waist-to-hip ratio, were additionally added to the model. Notably, the associations between leptin and hypertension were stronger in men, but were not different by race/ethnic group, BMI or smoking status. Adiponectin, resistin and TNFα were not independently associated with blood pressure or hypertension. Higher serum leptin, but not adiponectin, resistin or TNFα, is associated with higher levels of all measures of blood pressure, as well as a higher odds of hypertension, independent of risk factors, anthropometric measures and other selected adipokines.

Association of arterial rigidity with incident kidney disease and kidney function decline: the Health ABC study

BACKGROUND AND OBJECTIVE

The association of large arterial rigidity and kidney function decline in longitudinal analyses is not well established. This study evaluated the association of aortic pulse wave velocity (aPWV) and pulse pressure (PP) with rapid kidney function decline and incident CKD in the Health, Aging and Body Composition study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Participants were 2129 older adults with a baseline measurement of aPWV, PP, and cystatin C and at least one additional measurement of cystatin C, either at year 3 or year 10. Outcomes were rapid kidney function decline (estimated GFRcysC loss of >3 ml/min per 1.73 m(2) per year) and incident CKD (eGFRcysC < 60 ml/min per 1.73 m(2) in participants with baseline estimated GFR > 60 ml/min per 1.73 m(2)). Multivariate regression models were used to evaluate association of aPWV and PP with each outcome.

RESULTS

Mean (SD) baseline estimated GFRcysC was 79±29 ml/min per 1.73 m(2). Median follow-up duration was 8.9 years. In multivariable analyses, aPWV was not associated with rapid decline (odds ratio [OR], 95% confidence interval [CI] 1.16, 0.89-1.52) but was associated with incident CKD (incident rate ratio [IRR], 95% CI, 1.39, 1.09-1.77) and PP was associated with both rapid decline (OR, 95% CI 1.10, 1.04-1.16) and incident CKD (IRR, 95% CI, 1.06, 1.01-1.11).

CONCLUSIONS

Large arterial stiffness assessed by aPWV and pulsatility assessed by PP were associated with incident CKD among older adults. Pulsatility assessed by PP was associated with rapid kidney function decline and incident CKD. Future research should determine whether interventions targeting arterial rigidity will prevent CKD development and progression.

Fibroblast growth factor-23 and death, heart failure, and cardiovascular events in community-living individuals: CHS (Cardiovascular Health Study)

OBJECTIVES

This study sought to determine the association of fibroblast growth factor (FGF)-23 with death, heart failure (HF), and cardiovascular disease (CVD) in the general population, as well as the influence of chronic kidney disease (CKD) in this setting.

BACKGROUND

FGF-23 increases renal phosphorus excretion and inhibits vitamin D activation. In end-stage renal disease, high FGF-23 levels are associated with mortality. The association of FGF-23 with death, HF, and CVD in the general population, and the influence of CKD in this setting, are unknown.

METHODS

Plasma FGF-23 was measured in 3,107 community-living persons ≥ 65 years of age in 1996 and 1997, and participants were followed through 2008. HF and CVD events were adjudicated by a panel of experts. Associations of FGF-23 with each outcome were evaluated using Cox proportional hazards models, and we tested whether associations differed by CKD status.

RESULTS

Both lower estimated glomerular filtration rate and higher urine albumin to creatinine ratios were associated with high FGF-23 at baseline. During 10.5 years (median) follow-up, there were 1,730 deaths, 697 incident HF events, and 797 incident CVD events. Although high FGF-23 concentrations were associated with each outcome in combined analyses, the associations were consistently stronger for those with CKD (p interactions all <0.006). In the CKD group (n = 1,128), the highest FGF-23 quartile had adjusted hazards ratios (HR) of 1.87 (95% confidence interval [CI]: 1.47 to 2.38) for all-cause death, 1.94 (95% CI: 1.32 to 2.83) for incident HF, and 1.49 (95% CI: 1.02 to 2.18) for incident CVD events compared with the lowest quartile. Corresponding HRs in those without CKD (n = 1,979) were 1.29 (95% CI: 1.05 to 1.59), 1.37 (95% CI: 0.99 to 1.89), and 1.07 (95% CI: 0.79 to 1.45).

CONCLUSIONS

FGF-23, a hormone involved in phosphorous and vitamin D homeostasis, is independently associated with all-cause death and incident HF in community-living older persons. These associations appear stronger in persons with CKD.

Rapid decline of kidney function increases cardiovascular risk in the elderly

Chronic kidney disease (CKD), defined at a specific time point, is an important risk factor for cardiovascular disease. Whether the rate of kidney function decline contributes additional cardiovascular risk is unknown. In the Cardiovascular Health Study, we compared the associations of changes in kidney function during the first 7 yr with the incidence of heart failure (HF), myocardial infarction (MI), stroke, and peripheral arterial disease (PAD) during the subsequent 8 yr. We defined a rapid decline in cystatin C-based estimated GFR as >3 ml/min per 1.73 m(2)/yr, on the basis of determination at baseline, year 3, and year 7. Among eligible participants, 1083 (24%) had rapid kidney decline. The incidence of each type of cardiovascular event was significantly higher among patients with rapid decline (all P < 0.001). After multivariate adjustment for demographics, cardiovascular disease risk factors, and baseline kidney function, rapid kidney function decline was significantly associated with HF (adjusted hazard ratio [HR] 1.32; 95% confidence interval [CI] 1.13 to 1.53), MI (HR 1.48; 95% CI 1.21 to 1.83), and PAD (HR 1.67; 95% CI 1.02 to 2.75) but not with stroke (HR 1.19; 95% CI 0.97 to 1.45). The association of rapid decline with each outcome did not differ by the presence or absence of CKD. In conclusion, declining kidney function associates with higher risk for HF, MI, and PAD among patients with or without CKD.

Cystatin C and aging success

BACKGROUND

To our knowledge, the effect of kidney function on successful aging has not been examined.

METHODS

We evaluated the relationship between cystatin C and aging success during a 6-year follow-up in the Cardiovascular Health Study, a community-based cohort of older adults (aged >or= 65 years). Successful aging was defined as remaining free of cardiovascular disease, cancer, and chronic obstructive pulmonary disease and having intact physical and cognitive functioning. In adjusted analysis, an accelerated failure time model was used to evaluate the percentage reduction in successful years by level of cystatin C. A separate Cox proportional hazards model evaluated whether cystatin C was related to incident physical and cognitive disability.

RESULTS

A total of 2140 participants had cystatin C measured and were free of the previously mentioned conditions at baseline. Their mean age was 74 years. The mean cystatin C level, creatinine level, and estimated glomerular filtration rate were 1.06 mg/L, 0.93 mg/dL, and 78 mL/min/1.73 m(2), respectively (to convert cystatin C to nanomoles per liter, multiply by 75; and to convert creatinine to micromoles per liter, multiply by 88.4). A total of 873 participants reached a first event in follow-up, 138 because of cognitive disability, 238 because of physical disability, 34 because of chronic obstructive pulmonary disease, 146 because of cancer, and 317 because of cardiovascular disease. The adjusted percentage reduction in successful life years in the highest vs the lowest quartile of cystatin C was 27% (95% confidence interval, 11%-39%). The highest vs lowest quartile of cystatin C also was independently associated with incident cognitive or physical disability (hazard ratio, 1.39; 95% confidence interval, 1.00-1.98).

CONCLUSION

A higher cystatin C level, even within a range of relatively normal kidney function, was associated with unsuccessful aging.

Physician control of pediatric antimicrobial use in Beijing, China, and its rural environs

BACKGROUND

Antibiotic resistance is recognized as an increasing problem in China. It is widely believed that because antibiotics are available without a prescription, changing physician prescribing behaviors will not decrease inappropriate usage. This study identified the sources of antibiotics and the important influence that physicians have on antibiotic use by children in one region of China.

METHODS

Trained medical professionals surveyed parents of children attending several kindergartens in urban Beijing and rural Gu'An, Hebei County. Parents completed a questionnaire concerning the children's recent illnesses, care-seeking patterns and antibiotic use. The team also observed hospital- and non-hospital-based pharmacy purchases of antibiotics for children, assessed the proportion accompanied by a prescription and then interviewed parents about factors influencing those purchases.

RESULTS

Of 241 urban and 143 rural kindergarten parents, 76 to 82% usually obtained children's antibiotics from a hospital pharmacy (with a prescription). For 84% the first source of care was usually a physician (primarily western medicine, sometimes traditional Chinese medicine). Only 5% of antibiotics were obtained from independent vendors without prior physician consultation. Among 229 observed antibiotic purchases 72% occurred at hospital-based facilities, even after longer observation times at nonhospital pharmacies. Prescriptions accompanied all hospital-based antibiotic purchases, contrasting with 18% of nonhospital transactions (P < 0.001). Together 86% of parents self-reported that the observed purchase stemmed from a doctor's recommendation.

CONCLUSIONS

Doctors directly and indirectly controlled the majority of antibiotic usage for childhood illnesses in Beijing and Gu'An (Hebei County). Physician education and implementation of treatment guidelines might substantially reduce inappropriate antimicrobial usage and help prevent antimicrobial resistance in this region.

Ambient temperature modulates hypoxic-induced changes in rat body temperature and activity differentially

When rats, acclimated to an ambient temperature (T(a)) of 29 degrees C, are exposed to 10% O(2) for 63 h, the circadian rhythms of body temperature (T(b)) and level of activity (L(a)) are abolished, T(b) falls to a hypothermic nadir followed by a climb to a hyperthermic peak, L(a) remains depressed (Bishop B, Silva G, Krasney J, Salloum A, Roberts A, Nakano H, Shucard D, Rifkin D, and Farkas G. Am J Physiol Regulatory Integrative Comp Physiol 279: R1378-R1389, 2000), and overt brain pathology is detected (Krasney JA, Farkas G, Shucard DW, Salloum AC, Silva G, Roberts A, Rifkin D, Bishop B, and Rubio A. Soc Neurosci Abstr 25: 581, 1999). To determine the role of T(a) in these hypoxic-induced responses, T(b) and L(a) data were detected by telemetry every 15 min for 48 h on air, followed by 63 h on 10% O(2) from rats acclimated to 25 or 21 degrees C. Magnitudes and rates of decline in T(b) after onset of hypoxia were inversely proportional to T(a), whereas magnitudes and rates of T(b) climb after the hypothermic nadir were directly proportional to T(a). No hyperthermia, so prominent at 29 degrees C, occurred at 25 or 21 degrees C. The hypoxic depression of L(a) was least at 21 degrees C and persisted throughout the hypoxia. In contrast, T(a) was a strong determinant of the magnitudes and time courses of the initial fall and subsequent rise in T(b). We propose that the absence of hyperthermia at 21 and 25 degrees C as well as a persisting hypothermia may protect the brain from overt pathology.

Circadian rhythms of body temperature and activity levels during 63 h of hypoxia in the rat

The hypothermic response of rats to only brief ( approximately 2 h) hypoxia has been described previously. The present study analyzes the hypothermic response in rats, as well as level of activity (L(a)), to prolonged (63 h) hypoxia at rat thermoneutral temperature (29 degrees C). Mini Mitter transmitters were implanted in the abdomens of 10 adult Sprague-Dawley rats to continuously record body temperature (T(b)) and L(a). After habituation for 7 days to 29 degrees C and 12:12-h dark-light cycles, 48 h of baseline data were acquired from six control and four experimental rats. The mean T(b) for the group oscillated from a nocturnal peak of 38.4 +/- 0.18 degrees C (SD) to a diurnal nadir of 36.7 +/- 0.15 degrees C. Then the experimental group was switched to 10% O(2) in N(2). The immediate T(b) response, phase I, was a disappearance of circadian rhythm and a fall in T(b) to 36.3 +/- 0.52 degrees C. In phase II, T(b) increased to a peak of 38.7 +/- 0.64 degrees C. In phase III, T(b) gradually decreased. At reoxygenation at the end of the hypoxic period, phase IV, T(b) increased 1.1 +/- 0.25 degrees C. Before hypoxia, L(a) decreased 70% from its nocturnal peak to its diurnal nadir and was entrained with T(b). With hypoxia L(a) decreased in phase I to essential quiescence by phase II. L(a) had returned, but only to a low level in phase III, and was devoid of any circadian rhythm. L(a) resumed its circadian rhythm on reoxygenation. We conclude that 63 h of sustained hypoxia 1) completely disrupts the circadian rhythms of both T(b) and L(a) throughout the hypoxic exposure, 2) the hypoxia-induced changes in T(b) and L(a) are independent of each other and of the circadian clock, and 3) the T(b) response to hypoxia at thermoneutrality has several phases and includes both hypothermic and hyperthermic components.

Phenotypic variability of CADASIL and novel morphologic findings

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a non-arterio-atherosclerotic, non-amyloidotic arteriopathy affecting preferentially the small arteries and arterioles of the brain. The morphologic hallmark is the presence of a characteristic granular alteration of the arterial media that ultrastructurally corresponds to the accumulation of electron-dense material surrounding the smooth muscle cells. Although the presence of this granular osmiophilic material (GOM) was originally described as limited to brain vessels, identical electron microscopic findings have been demonstrated in the media of peripheral tissue arteries, allowing for a pathologic diagnosis of the disease by a simple skin, muscle or nerve biopsy. We report some atypical features identified in our CADASIL patients that broaden the phenotypic expression of this disease. Firstly, we identified a cortical infarct in an otherwise typical CADASIL patient. Secondly, we observed GOM in skin arteries of a 30-year-old man with hemiplegic migraine, the son of a woman who had died with CADASIL. This confirms that it may be possible to diagnose the disease at a preclinical stage by the ultrastructural evaluation of peripheral tissue biopsy material, particularly for individuals for whom there is a supporting family history. Thirdly, ultrastructural examination of the skin, and subcutaneous and striated muscle of an unrelated and apparently sporadic patient with neuropathologic and neuroradiologic evidence of CADASIL in meningeal and cerebral vessels failed to reveal diagnostic lesions in peripheral arteries. Thus, the possibility of a false-negative pathologic diagnosis in patients with a clinicoradiologic diagnosis of CADASIL, if one relies solely on a peripheral tissue biopsy, does exist. Additionally, we have identified heat shock proteins (Hsp70 and alphaB crystallin) and ubiquitin in the vascular myocytes of affected arteries. <alpha>B crystallin also seemed to be deposited extracellularly, which suggests that GOM also might be immunoreactive for alphaB crystallin.

Characterization of a temperature-sensitive membrane alteration in chick embryo fibroblasts infected with a temperature-sensitive mutant of Rous sarcoma virus

The intramembrane particles of freeze-fractured chick embryo fibroblasts transformed with a temperature-sensitive mutant of Rous sarcoma virus (TS68) are distributed differently at the permissive and non-permissive temperatures if, and only if, the cells are treated with glycerol before fixation. Few aggregates of intramembrane particles are present in glycerol-treated cells grown at the permissive temperature for transformation (36 degrees C), while numerous large aggregates of particles are present at the non-permissive temperature (41 degrees C). Changes in the distribution of particles after cells are shifted from 36 to 41 degrees C are observed after 20 min, while a temperature shift from 41 to 26 degrees C causes changes in glycerol-induced redistributions after 1 h. The changes observed in temperature shifts from 36 to 41 degrees C and from 41 to 36 degrees D do not require protein synthesis or RNA synthesis.

Phenotype of polyoma-induced hamster tumor cells lines

Cell lines from polyoma-induced hamster tumors exhibit a fully transformed phenotype despite the absence of the 105K (105,000-dalton) form of polyoma T-antigen.

Tumorigenicity of revertant from an SV40-transformed line

A syndrome of in vitro properties correlates with the tumorigenicity of SV40-transformed rodent cells. These properties are: plasminogen activator production, loss of large actin cables, and anchorage-independent growth. An established rat fibroblast line, its SV40 transformant, several T-antigen negative revertants, and a spontaneous retransformant isolated from one of the revertants were analyzed in vivo for their tumorigenicity and in vitro for the syndrome. The two transformed lines were highly tumorigenic, and had clearly abnormal in vitro properties. The parental rat line was weakly tumorigenic in nude mice and demonstrated a slightly transformed response in the in vitro assays. The revertants were completely nontumorigenic. Expression of the in vitro syndrome was not uniform for all revertants; however, most cell lines maintained the correlation of the syndrome and tumorigenicity.

The characterization of SV40-transformed cell lines derived from mouse teratocarcinoma: growth properties and differentiated characteristics

Mouse teratocarcinoma cells derived from embryoid bodies of 129SVsl mice were cultured in vitro to permit their differentiation. These cells were then infected with simiam virus 40 (SV40) and 31 cloned cell lines (SVTER) were derived from these cultures. All 31 SVTER cell lines contained the SV40 tumor (T) antigen and grew as permanent lines in culture. Mock-infected embryoid body cultures did not give rise to permanent cell lines. The morphology of each SVTER cell line was distinct and did not change during successive subclonings. The growth properties and tumorigenic potential of all 31 SVTER cell lines were investigated. None of these lines produced tumors in 129SVsl mice. Each cell line was tested for its ability to (1) grow in medium containing 1% serum, (2) plate on cell monolayer, and (3) form clones in methocel suspension. Only three of the SVTER cell lines were transformed with respect to all three of these criteria. Most of these cell lines were minimal transformants. The SVTER cell lines were tested for creatine phospholinase (CPK), an enzyme activity chracteristic of mouse brain and muscle tissue, and the protease, plasminogen activator (PA) which is found in embryoid bodies and several differentiated cell types. Some of the SVTER cell lines contained high levels of CPK, while others had high levels of PA and a third group of cells contained neither enzyme activity. No SVTER cell line was found with high levels of both these enzyme activities. This result suggests that mutually exclusive sets of genes are expressed in these cells as might be expected from the distinct tissue distribution of the two enzyme activities studied. These SVTER cell lines may be useful in reconstructing developmental pathways of differentiating teratomas in vitro.

In vitro differentiation of teratomas and the distribution of creatine phosphokinase and plasminogen activator in teratocarcinoma-derived cells

Mouse teratocarcinoma cells from embryoid bodies were cultured in vitro to permit their differentiation into a number of cell types. Two enzyme activities, creatine phosphokinase (CPK) and the protease plasminogen activator, were studied to follow the developmental sequence of events in these embryoid body-derived cell cultures. CPK activity increased with time in culture, indicating the appearance of new cell types with brain- or muscle-specific enzyme activities. Plasminogen activator was detectable in extracts of embryoid bodies. This protease activity first increased and then decreased to a low level as the embryoid bodies in culture developed into differentiated cell types. These cell cultures also showed a decreased potential for tumor formation in syngeneic mice as a function of time in culture. This decrease in tumorigenic potential was correlated with the appearance of differentiated cells in vitro. Simian virus 40 (SV40) was used to infect and transform cells derived from embryoid bodies in culture. This was done to permit the establishment of cloned teratocarcinoma-derived cell lines. Twenty-nine distinct cloned permanent cell lines (called SVTER) containing the SV40-specific tumor antigen were obtained. None of these cell lines was capable of producing tumors in syngeneic mice. An analysis of the levels of creatine phosphokinase and plasminogen activator in these SVTER cell lines indicated that : (a) some cell lines had high CPK activity and little or no plasminogen activator activity, (b) some cell lines contained high levels of plasminogen activator activity with little or no CPK activity, and (c) some cell lines contained neither of these enzyme activities. No example of a cell line with high levels of both enzyme activities was observed, indicating that these two enzymes may participate in mutually exclusive developmental pathways. The SVTER cell lines may therefore be useful in reconstructing these developmental pathways in vitro.

Plasminogen activator production accompanies loss of anchorage regulation in transformation of primary rat embryo cells by simian virus 40

We have isolated several lines of rat embryo cells transformed by simian virus 40. All these lines are fully transformed with regard to saturation density and serum sensitivity, but they differ greatly in their anchorage dependence, as assayed by efficiency of plating in methyl cellulose suspension. This set of lines reveals a consistent relation of plasminogen activator production to plating efficiency in methyl cellulose. T-antigen-positive transformed lines that synthesize activator grow in methyl cellulose suspension, while T-antigen-positive transformed lines that do not synthesize activator fail to form colonies in suspension. Normal rat embryo cells produce very little plasminogen activator and do not grow in methyl cellulose. Sera that permit high levels of plasmin formation and activity support growth in semi-solid medium better than sera whose plasminogen is activated poorly and/or sera that contain inhibitors to plasmin.